1. Field of the Invention
This invention relates to an automatic opening and closing device, and more particularly to an automatic opening and closing device for back doors in automobiles.
2. Description of the Related Art
A conventional opening and closing device for a back door is disclosed in Japanese Utility Model Laid Open Publication No. 63(1988)-6927 published without examination on Jan. 1, 1988.
In this conventional opening and closing device for a back door an opening portion is formed in a rear portion of a body in an automobile. A back door is rotatably supported to an upper portion of the opening portion for opening and closing the same. A pair of damper stays are provided on both side portions of the opening portion and are operatively connected to the back door and the portion of the body. A lock mechanism is mounted on the back door and the rear portion of the body, respectively so as to lock the back door to the rear portion of body in closed condition of the opening portion.
The operation of the foregoing device will be explained as follows;
Upon opening of the back door, the lock mechanism is released from the locking position by key operation and then the back door is upwardly lifted by manual power. After the back door is lifted at a certain angle, the back door can be lifted at larger angle because the back door is assisted to be lifted by means of the damper stays. As a result, the back door can be moved to the open condition. Baggages can be picked up from a baggage space through the opening portion communicating with the baggage space. To close the back door, the back door is downwardly pushed by manual power. Thereafter, the back door is assisted to be lowered by the weight thereof against the damper stays. As a result, the back door can be moved to the close condition.
An operator has to open and close the back door from the outside of automobiles because the back door has to be lifted and lowered by manual power. As a result, the back door can not be operated from an interior of automobiles by the operator.